Mark L. Roberts

Mark Roberts, staff physicist is working on an initiative to re-determine the 14C half-life. This initiative was developed in response to questions raised by various researchers at Lamont-Doherty Earth Observatory (Broecker, 2005; Fairbanks, 2005; Chiu, 2007), who pointed to uncertainties about the validity of the 'accepted' 14C half-life. These groups suggested that the currently accepted half-life of 5700 ± 30 years might be too low. A significant shift in the 14C half-life would impact our understanding of the 14 C calibration curve. Preliminary results, in which the 14C half-life is determined from knowledge of both the specific-activity and 14C/12C ratio of the 14C counting standard OX-I, indicate that the currently accepted half-life might actually be 1-2% too high. A paper summarizing the work has been recently accepted for publication in Radiocarbon.